So why aren't as many farmers growing hops and barley? Because the government is paying them ridiculous jack to grow corn so we can burn food into our cars:

Papazian attributed the barley prices to ethanol subsidies that have
raised the price of corn, the main ingredient in the alternative fuel.
As a result, farmers have switched to barley for livestock feed, which
has pushed up prices.

The hops situation is more complex. Years of overproduction and low
prices led farmers to replace hops fields with more profitable crops.
Add to that corn subsidies that have caused farmers to replace hops
fields with corn, a drought in Australia that affected yields and heavy
rains in Europe that ruined much of this year's crop.